GeoMelt is a process by which dangerous, contaminated material (such as radioactive waste and heavy metals) is mixed with clean soil, a blend of industrial minerals, and/or glass frit and melted to create an extremely hard and leach-resistant glass product. Vitrification immobilizes nearly all of the inorganic contaminants (i.e., radionuclides and heavy metals) present in the initial mixture by incorporation into the glass matrix. Organic wastes in the melt are destroyed by pyrolysis, and gaseous contaminants released during the melting process are treated separately. Developed in 1980 by the U.S. Department of Energy's Pacific Northwest National Laboratory (PNNL), the GeoMelt process is deployed in one of two ways: in-situ (in-place) treatment of buried radioactive and hazardous wastes, and In-Container Vitrification (ICV), which is ex-situ treatment where radioactive and hazardous wastes are vitrified in a refractory-lined steel container. Process Vitrification Geomelting is based on the principle of vitrification, the process by which a glass is formed. To effectively vitrify any mixture of materials, substances that contribute to glass formation (called glass formers) must be present. These glass formers usually contain silicon and oxygen and are present in most soils. Much of the efficiency of this process has to do with how much waste material can be mixed with glass formers. Industrial-scale melts have shown that a stable glass compound is formed even when the original melt mixture is up to 33-40% waste material by weight, depending on the type of waste. Melting First, waste is mixed with soil containing glass formers in a large container installed with electrodes (electrical conductors) suitable for heating the mixture. The container used is either underground (subsurface planar vitrification, or SPV) or above ground (in-container vitrification, or ICV). In both cases, the waste/soil mixture is loaded into the container and the heating processes begins when the electrodes are turned on. Due to spatial restrictions, the entire mixture cannot melt at the same time. The materials closest to the electrodes are melted first, and convection currents (movements of substances in a fluid) within the molten mixture continue to add more solid material into the molten material. After about 36-58 hours, all of the mixture is molten and the convection currents create homogeneity (equal distribution of components) within the resultant mixture. Subsurface Planar Vitrification (SPV) In subsurface planar vitrification, all melting operations are performed at the site of contamination. A very tall (around 6 meters deep), narrow cavern